Field of the Invention
The present invention relates to an image forming apparatus, an image forming system, and a non-transitory storage medium for forming an image on a recording medium based on image data transmitted from a data processor such as a personal computer.
Description of the Related Art
There is conventionally known an image forming apparatus such as a printer and a facsimile machine communicably connected to a data processor such as a personal computer and configured to print an image and/or texts on a recording medium based on image data transmitted from the data processor. Such an image forming apparatus does not perform the printing immediately for the image data transmitted from the data processor to the image forming apparatus, and a user commands the printing at the image forming apparatus to perform the printing (noted that this printing is called a storage print because the print data is temporarily stored). One example of the image forming apparatus is one having an identification printing function. This identification printing function is a function in which a user permitted to perform the printing and having made the print request performs an identification operation at the image forming apparatus in order for the image forming apparatus to identify the print job, and, if the identification operation has succeeded, the printing of the print job is allowed. Specifically, the user requests the printing at the data processor by entering authentication information (e.g., an ID and a password). The image forming apparatus detects that the print request contains the authentication information and registers the print request as a print job with the authentication information (which is called an authentication print job). The user having made the print request enters the authentication information at the image forming apparatus. If the entered authentication information is correct, the image forming apparatus allows the printing of the authentication print job. This identification printing function is mainly used when confidential documents are printed, for example.
Another example of the image forming apparatus is one configured such that the image data transmitted from the data processor to the image forming apparatus is stored into the image forming apparatus, and the printing is performed by the user commanding the printing at the image forming apparatus for the image data. This apparatus does not have the identification function, but a plurality of users can print the image data stored in the image forming apparatus on demand.
If the image forming apparatus is always kept in a standby state in which a power source of the apparatus is ON such that the printing can be started immediately, an electric power for the standby state is consumed even when the printing is not performed. In order to save the power consumption, if a next print job has not been received within a predetermined standby time, or the image forming apparatus has not been operated by the user within the predetermined standby time, the image forming apparatus enters a power saving mode (hereinafter may be referred to as “sleep mode”) after a lapse of the standby time. The power saving mode is a mode in which the supply of the power to some circuits or the apparatus is stopped or reduced. With increasing demand for a power-saving image forming apparatus, there has been developed an apparatus in which the apparatus enters the sleep mode even if the image forming apparatus is not operated within a short length of time, e.g., 15 seconds. This sleep mode is exited when the next print job arrives, or the user performs an appropriate operation on the image forming apparatus.